Real-world evidence on palmoplantar pustulosis: Patient characteristics, diagnostic challenges and predictive factors for treatment survival - a retrospective registry study

Abstract

Introduction: Little is known about the clinical characteristics, delay in diagnosis and treatment survival in patients with palmoplantar pustulosis (PPP).

Methods: This is a retrospective study using data from the Psoriasis Registry Austria (PsoRA).

Results: This study included data from 190 patients, who underwent 397 treatments. A substantial proportion of patients (53.6%) were initially misdiagnosed as having eczema with a mean (standard deviation) diagnostic delay of 2.8 years (4.8). Patients were predominantly female (74.2%) and smokers (77.6%). Patients were treated with biologics (49.9%), phototherapy (25.2) and conventional systemic therapies (24.9%). The median survival time (95% confidence interval) for all treatments was 0.6 years (0.5-0.8), with ustekinumab having the longest median survival time of 2.7 years (2.3 - upper limit not reached), surpassing all other therapies. However, this superiority disappeared after IL-23p19 inhibitors were introduced in Austria. Compared to biologics, conventional systemic treatments (hazard ratio [HR] 2.17, p < 0.001) and phototherapy (HR 4.43, p < 0.001) were associated with a significantly higher risk of treatment discontinuation. In the overall cohort, disease duration of ≥ 2 to < 10 years (HR 0.66, p = 0.049) and ≥ 10 years (HR 0.59, p = 0.004) significantly reduced the risk of treatment discontinuation, while concomitant plaque psoriasis significantly increased the risk for treatment discontinuation (HR 1.43, p = 0.049). In the biologic cohort, concomitant arthritis (HR 2.11, p = 0.002) and the presence of one comorbid disease (HR 2.34, p = 0.026) increased the risk for treatment discontinuation. Furthermore, gender, age at disease onset and smoking did not influence the risk of treatment discontinuation.

Conclusion: The findings of this cohort suggest that more than half of patients experienced a diagnostic delay of several years due to an initial misdiagnosis. Among all therapies, the IL-12/23p40 inhibitor ustekinumab showed the longest treatment survival. However, its superiority diminished with the introduction of IL-23p19 inhibitors. Finally, shorter disease duration and concomitant plaque psoriasis was identified as a general risk factor for treatment discontinuation, while the presence of comorbidity and presence of concomitant psoriatic arthritis were identified as risk factors for discontinuation of biologic treatment.